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       1                 :            : /*
       2                 :            :  * Author: Simon McVittie <simon.mcvittie@collabora.co.uk>
       3                 :            :  * Copyright © 2011 Nokia Corporation
       4                 :            :  *
       5                 :            :  * SPDX-License-Identifier: LGPL-2.1-or-later
       6                 :            :  *
       7                 :            :  * This program is free software; you can redistribute it and/or
       8                 :            :  * modify it under the terms of the GNU Lesser General Public
       9                 :            :  * License as published by the Free Software Foundation; either
      10                 :            :  * version 2.1 of the License, or (at your option) any later version.
      11                 :            :  *
      12                 :            :  * See the included COPYING file for more information.
      13                 :            :  */
      14                 :            : 
      15                 :            : #ifndef GLIB_DISABLE_DEPRECATION_WARNINGS
      16                 :            : #define GLIB_DISABLE_DEPRECATION_WARNINGS
      17                 :            : #endif
      18                 :            : 
      19                 :            : #include <glib.h>
      20                 :            : 
      21                 :            : static GStaticPrivate sp;
      22                 :            : static GMutex *mutex;
      23                 :            : static GCond *cond;
      24                 :            : static guint i;
      25                 :            : 
      26                 :            : static gint freed = 0;  /* (atomic) */
      27                 :            : 
      28                 :            : static void
      29                 :       2000 : notify (gpointer p)
      30                 :            : {
      31         [ -  + ]:       2000 :   if (!g_atomic_int_compare_and_exchange (&freed, 0, 1))
      32                 :            :     {
      33                 :          0 :       g_error ("someone already freed it after %u iterations", i);
      34                 :            :     }
      35                 :       2000 : }
      36                 :            : 
      37                 :       2000 : static gpointer thread_func (gpointer nil)
      38                 :            : {
      39                 :            :   /* wait for main thread to reach its g_cond_wait call */
      40                 :       2000 :   g_mutex_lock (mutex);
      41                 :            : 
      42                 :       2000 :   g_static_private_set (&sp, &sp, notify);
      43                 :       2000 :   g_cond_broadcast (cond);
      44                 :       2000 :   g_mutex_unlock (mutex);
      45                 :            : 
      46                 :       2000 :   return nil;
      47                 :            : }
      48                 :            : 
      49                 :            : static void
      50                 :          2 : testcase (void)
      51                 :            : {
      52                 :            :   /* On smcv's laptop, 1e4 iterations didn't always exhibit the bug, but 1e5
      53                 :            :    * iterations exhibited it 10/10 times in practice. YMMV.
      54                 :            :    *
      55                 :            :    * If running with `-m slow` we want to try hard to reproduce the bug 10/10
      56                 :            :    * times. However, as of 2022 this takes around 240s on a CI machine, which
      57                 :            :    * is a long time to tie up those resources to verify that a bug fixed 10
      58                 :            :    * years ago is still fixed.
      59                 :            :    *
      60                 :            :    * So if running without `-m slow`, try 100× less hard to reproduce the bug,
      61                 :            :    * and rely on the fact that this is run under CI often enough to have a good
      62                 :            :    * chance of reproducing the bug in 1% of CI runs. */
      63         [ -  + ]:          2 :   const guint n_iterations = g_test_slow () ? 100000 : 1000;
      64                 :            : 
      65                 :          2 :   g_test_bug ("https://bugzilla.gnome.org/show_bug.cgi?id=642026");
      66                 :            : 
      67                 :          2 :   mutex = g_mutex_new ();
      68                 :          2 :   cond = g_cond_new ();
      69                 :            : 
      70                 :          2 :   g_mutex_lock (mutex);
      71                 :            : 
      72         [ +  + ]:       2002 :   for (i = 0; i < n_iterations; i++)
      73                 :            :     {
      74                 :            :       GThread *t1;
      75                 :            : 
      76                 :       2000 :       g_static_private_init (&sp);
      77                 :       2000 :       g_atomic_int_set (&freed, 0);
      78                 :            : 
      79                 :       2000 :       t1 = g_thread_create (thread_func, NULL, TRUE, NULL);
      80                 :       2000 :       g_assert (t1 != NULL);
      81                 :            : 
      82                 :            :       /* wait for t1 to set up its thread-private data */
      83                 :       2000 :       g_cond_wait (cond, mutex);
      84                 :            : 
      85                 :            :       /* exercise the bug, by racing with t1 to free the private data */
      86                 :       2000 :       g_static_private_free (&sp);
      87                 :       2000 :       g_thread_join (t1);
      88                 :            :     }
      89                 :            : 
      90                 :          2 :   g_cond_free (cond);
      91                 :          2 :   g_mutex_unlock (mutex);
      92                 :          2 :   g_mutex_free (mutex);
      93                 :          2 : }
      94                 :            : 
      95                 :            : int
      96                 :          2 : main (int argc,
      97                 :            :     char **argv)
      98                 :            : {
      99                 :          2 :   g_test_init (&argc, &argv, NULL);
     100                 :            : 
     101                 :          2 :   g_test_add_func ("/glib/642026", testcase);
     102                 :            : 
     103                 :          2 :   return g_test_run ();
     104                 :            : }